Population Trends in Illinois Highlight Regional Disparities
Data from the U.S. Census reveals minimal population change in Cook County during 2025, primarily attributed to a decrease in international immigration. In contrast, Kendall County defied this national trend, registering the highest growth rate among Illinois counties.
Cook County Experiences Marginal Growth
Cook County’s population increased by approximately 5,834, a growth rate of just 0.1% from July 1, 2024, to July 1, 2025. This figure reflects a broader struggle faced by many regions coping with fluctuating immigration patterns post-pandemic.
Suburban Growth of Kendall and Will Counties
While Cook County’s growth remained stagnant, the southwest suburbs are thriving. Kendall County, for instance, recorded a notable increase of 1.6%, translating to around 14,000 new residents. Will County also observed a significant uptick, with an additional 15,000 newcomers, representing a growth of 0.5%.
Kendall County’s Development Resurgence
Kendall County Governor Christina Burns remarked that her region has regained growth levels reminiscent of the period before the 2008 recession, when it was recognized as the fastest-growing county in the nation. This resurgence in population is driven by families seeking to establish roots in a vibrant community.
Yorkville’s Housing Expansion
Yorkville’s Mayor John Purcell highlighted his town’s impressive housing growth last year, despite a decline from previous peak levels. The draw of Yorkville can be attributed to its favorable location outside the metropolitan growth ring and the affordability of housing, along with a reputation for safety and community amenities.
Statewide Population Stability Amid Decline Since 2020
Illinois’ overall population reached 12,719,141 in 2025, showing minor variations from the prior year yet reflecting a decrease of 102,600 residents, or 0.8%, since 2020. This decline is largely a legacy of the population shifts triggered by the COVID-19 pandemic.
Broader National Trends Reflect Slower Growth
Nationally, the trend mirrors that of Cook County, with the majority of the 3,143 counties in the United States witnessing a slowdown in population growth. Of the 2,066 counties that did grow from 2023 to 2024, nearly 80% saw a deceleration or reversal in their growth rate by 2025, exacerbating challenges in already declining areas.
Impact of International Immigration Declines on Population Dynamics
Many of the nation’s largest counties have felt the most significant effects of reducing international immigration. Typically, these counties recorded higher birth rates than death rates, but they also faced extensive out-migration, resulting in slower or declining growth trends. George Heyward, a Census Bureau demographer, noted that the diminished influx of international migrants has contributed to these shifts, particularly in urban centers such as New York.
